HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Interpretive Summary Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Emmanuel, D. G. V. Articles by Ametaj, B. N. PubMed PubMed Citation Articles by Emmanuel, D. G. V. Articles by Ametaj, B. N.

Acidosis and Lipopolysaccharide from Escherichia coli B:055 Cause Hyperpermeability of Rumen and Colon Tissues

D. G. V. Emmanuel^*, K. L. Madsen, T. A. Churchill, S. M. Dunn^* and B. N. Ametaj^*,1

^* Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
Department of Medicine, Division of Gastroenterology, University of Alberta, Edmonton, Alberta T6G 2C8, Canada
Surgical Medical Research Institute, University of Alberta, Edmonton, Alberta T6G 2N8, Canada

¹ Corresponding author: burim.ametaj{at}ualberta.ca

The objective of the present investigation was to evaluate the effects of acidic pH of the perfusate and presence of lipopolysaccharide (LPS) on permeability of rumen and colon mucosal tissues to mannitol and LPS using the Ussing chamber system. Rumen and colon tissues (n = 8), obtained from slaughtered feedlot steers, were tested for changes in permeability to ³H-mannitol under pH of 4.5, 5.5, and 6.5 for rumen and at 5.5, 6.5, and 7.4 for colon, with or without LPS from Escherichia coli B:055 at 500 µg/mL. The ³H-Mannitol was added at 10 µL (525.4 GBq/mmol) on the mucosal side of the Ussing chamber to detect changes in permeability, and 4 samples were taken at 20, 25, 30, and 35 min from the serosal side. Permeability of rumen and colon mucosa to ³H-mannitol increased 6- and 5-fold, respectively, at acidic pH values of 4.5 and 5.5 and in the presence of 500 µ/mL of LPS. In contrast, LPS did not affect rumen and colon permeability at pH that ranged from 5.5 and 7.4. Translocation of LPS across the rumen and colon mucosa of cattle was not pH dependent. The LPS translocated through these tissues if present at the mucosal side. In conclusion, the permeability of rumen and colon tissues to ³H-mannitol increased in presence of LPS and under acidic pH, whereas LPS permeated through mucosal tissues independently of the pH of the perfusate. Further research is warranted to understand the mechanism(s) by which acidic pH of the rumen digesta and presence of LPS make rumen and colon tissues "leaky".

Key Words: cattle • acidosis • lipopolysaccharide • mucosal permeability